It's something I really grappled with at the beginning: the Stockholm-syndrome question. That's where a prisoner will take on the characteristics of and fall in love with the captor.
She has none of the characteristics of someone with Stockholm syndrome because she keeps her independence; she keeps that freedom of thought.

Watson continued,

I also think there is a very intentional switch where, in my mind, Belle decides to stay. She's giving him hell. There is no sense of 'I need to kill this guy with kindness.' Or any sense that she deserves this.
In fact, she gives as good as she gets. He bangs on the door, she bangs back. There's this defiance that 'You think I'm going to come and eat dinner with you and I'm your prisoner -- absolutely not.'

Speaking further on the romance between Belle and the Beast, and what she hopes to bring to the role, Emma Watson said,

The other beautiful thing about the love story is that they form a friendship first. There is this genuine sharing, and the love builds out of that, which in many ways is more meaningful than a lot of love stories, where it was love at first sight. They are having no illusions about who the other one is.
They have seen the worst of one another, and they also bring out the best.
What's so beautiful about this story as a whole is this idea that Belle is able to see past these extraneous, external, superficial qualities of Beast. She is able to see deeper, and that's one of her special powers.
It is her superpower: empathy.

Interesting take. I think it's safe to assume Emma Watson has done her research for this role, so she's probably as good an authority as any on the whole Stockholm syndrome debate.

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Emma Watson also addressed the other male lead in "Beauty and the Beast," Gaston, who is played by Luke Evans.

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She said,

I think she can see in Beast that there's someone who has been fundamentally good who has been damaged and who just needs rehabilitating.
He is just in need of love, whereas Gaston is someone who has had nothing but love and admiration and easiness, and because he's never suffered, he doesn't have any empathy.
He's essentially a narcissist, and it's very difficult to intervene in that. He's about building himself up while pushing others down.

Woof! Better luck in the next life, Gaston!

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Don't forget, you can catch "Beauty and the Beast" in theaters March 17, 2017.